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SUMMARY This paper presents a novel type of flux-modulating synchronous machine (FMSM) in which permanent magnets (PMs) are embedded in the stator back-iron. The rotor has neither windings nor PMs. A prototype machine with an outer-rotor configuration was designed and manufactured to validate the operating principle of the FMSM. The characteristics in the motor mode of the prototype machine were also investigated with a vector control system. The results of the investigations show that, as in surface-mounted PM motors, the torque of the FMSM is predominantly generated by the PM flux and can be controlled using the armature current. [ABSTRACT FROM AUTHOR]

This paper investigates the appropriate permanent magnet (PM) arrangement of novel flux-modulating synchronous machines (FMSMs) in which PMs are embedded in the stator back iron. Using finite element analysis (FEA), three types of FMSMs with different PM arrangements are designed, and their performance characteristics are compared. As a result of the investigation, it was found that the FMSM with a V-shaped PM arrangement has a higher torque capability than do other FMSMs. The accuracy of the FEA simulations was confirmed through experiments on a prototype machine. [ABSTRACT FROM AUTHOR]

SUMMARY The flux-modulating synchronous machine (FMSM) is a new type of multipole SM with nonoverlapping concentrated armature and field windings on the stator. This paper compares the output characteristics of two FMSMs through finite element analysis (FEA) and experiments. In both of the FMSMs, the attachment positions of the armature and field windings are swapped. To determine the reason for the discrepancies in their output characteristics, unsaturated inductances were calculated using a d- -q equivalent circuit. In addition, the calculated results of the inductances were confirmed through a visualization of the leakage fluxes using FEA. The results of the study show that the synchronous inductance can be reduced by attaching the armature winding to the air-gap side of the stator teeth and that the reduction leads to an increase in output power. [ABSTRACT FROM AUTHOR]

In this paper, the core losses that occur in a 4-kVA flux-modulating synchronous machine (SM) (FMSM) are investigated using 2-D finite-element analysis, and the results are supported by experiments. A method for reducing the core losses is also presented. The FMSM is a new type of multipole SM in which the stator field magnetomotive force is modulated by the air-gap permeance to generate the rotating field. A 2pa-pole three-phase armature winding and a 2pf-pole field winding are centrally wound around individual stator teeth, and a reluctance rotor with 2pr\ (= pa + pf) saliencies is used to provide a magnetic coupling between these windings. As a result of the investigation, it was found that, although the core losses occur in the rotor as well as in the stator, the rotor core loss can be effectively reduced by decreasing the height of the rotor poles. [ABSTRACT FROM AUTHOR]

This paper presents a new type of multipole synchronous machine (SM) in which 2pa-pole armature and 2pf-pole field windings are centrally wound around individual stator teeth. The proposed machine operates as a (2pa + 2pf)-pole SM by providing a magnetic coupling between the armature and field windings through a 2pr-pole reluctance rotor. A 4-kVA (32 + 48)-pole prototype machine was designed and built to validate the principle of this structure. Performance characteristics of the prototype machine were simulated using 2-D finite-element analysis (FEA) and were supported by experiments. In addition, the effects of the rotor pole shape on the performance characteristics were studied through 2-D FEA simulations. The results presented provide guidelines for the optimum design of the proposed machine. [ABSTRACT FROM PUBLISHER]

The characteristic improvements of salient-pole synchronous generators by inserting additional permanent magnets are investigated from both results of finite-element analyses and experiments. First, the assist effects of the magnets in a megavoltampere-class generator are analyzed by the finite-element method. It is clarified that the additional permanent magnets have the effects of reducing magnetic saturation at the rotor-pole bodies, as well as the effects of increasing the direct flux linkage of armature windings. It is also clarified that the output of the generator can be increased by more than 20% by inserting the magnets without any increase in total machine size and decrease in efficiency. Finally, the characteristic improvements are validated by the experiment of a small prototype generator. The experimental and calculated results are found to be in good agreement. [ABSTRACT FROM PUBLISHER]